Package substrate, integrated circuit apparatus, substrate unit, surface acoustic wave apparatus, and circuit device

ABSTRACT

On a piezoelectric substrate  23 , there are provided surface acoustic wave devices F 1  and F 2  in which predetermined circuit patterns are formed, and a package substrate  11  comprising side vias  16  formed in a caved manner in the thickness direction on side surfaces on which the surface acoustic wave devices are mounted. When the side vias  16  are each assumed to have the opening width φ and the maximum depth D, a size satisfying φ/2&lt;D is assumed. Thereby, it is possible to prevent protrusion of a soldering fillet applied on the side via.

The present Application is a Divisional Application of U.S. patentapplication Ser. No. 10/253,991, filed on Sep. 25, 2002 now U.S. Pat.No. 7,151,310.

BACKGROUND OF THE INVENTION

The present invention relates to a package substrate, integrated circuitapparatus, substrate unit, surface acoustic wave apparatus, and circuitdevice, particularly to a surface acoustic wave device.

Today, mobile communication devices represented by portable phones whichhave been remarkably spread are being rapidly making smaller in size.Along with this, reduction in size and high performance are requestedfor parts used in the mobile communication devices. Here, frequencydividers are used for conducting branching and generating of signals inthe mobile communication devices. Some frequency dividers are configuredwith a bandpass filter, band rejection filter, or a combination thereof,but other frequency dividers employ a surface acoustic wave apparatus onwhich two surface acoustic wave devices having mutually differentbandpass center frequencies are mounted in order to achieve morereduction in size and higher performance.

Mounting substrates on which such a surface acoustic wave apparatus ismounted have been also made smaller in size and weight. Therefore, it isrequired that the surface acoustic wave apparatus is mounted on themounting substrate in a high density manner. In some package substratesof the surface acoustic wave apparatuses, side vias are formed in acaved manner in the thickness direction in side surfaces. When such asurface acoustic wave apparatus is soldered on the mounting substrate, asoldering fillet applied on the side via is protruded so that themounting area is increased, thereby the aforementioned request of thehigh density mounting cannot be achieved. Such a problem is not onlytrue to the surface acoustic wave apparatuses, but also to generalintegrated circuit apparatuses on which integrated circuit devices aremounted on the package substrate.

Further, when the frequency divider is configured with two surfaceacoustic wave devices having mutually different bandpass centerfrequencies, in order that the mutual filter characteristics are notinterfered, phase adjusting circuits are provided in the respectivedevices. The phase adjusting circuits are within the package with amultilayer structure made of ceramics (for example, alumina ceramics orglass ceramics) together with the surface acoustic wave devices toconfigure the package of the frequency divider which is the surfaceacoustic wave apparatus.

Here, a section view of the package of the frequency divider with themultilayer structure is shown in FIG. 17. In the illustrated package 100of the frequency divider, a device mounting layer 101 on which twosurface acoustic wave devices F₁ and F₂ having mutually differentbandpass center frequencies are mounted is provided as the uppermostlayer, a ground layer 102 in which ground electrodes are formed, acircuit forming layer 103 in which high frequency circuits such as phaseadjusting circuits are formed, and the lowermost layer which is asubstrate connecting layer 104 in which common ground electrodes orexternal connecting terminals are formed are positioned toward the lowerlayers from the uppermost layer, and the surface acoustic wave devicesF₁ and F₂ are airtightly sealed by a cap 106. Interlayers areappropriately connected by via holes 108 in an electric manner.

Here, in the frequency divider, various elements such as specificationsof high frequency circuits or wiring lengths are determined so as tohave specific electric frequency characteristics. In order to obtaininitial frequency characteristics, there is configured such that onlythe lowermost layer or uppermost layer is penetrated, and the portionsin which wirings are not led therefrom, that is open stubs are notgenerated. For the purpose of that, the aforementioned ceramics capableof electrically connecting only the required interlayers are used assubstrate materials, or the number of laminates is increased in order toavoid the open stubs so that wirings are connected.

However, when the number of laminates is increased in order to avoid theopen stubs, the package of the frequency divider is increased in sizeand cost thereof is also increased. Such a problem is not only true tothe package of the frequency divider, but also to general surfaceacoustic wave apparatuses.

Further, in order to obtain larger output, reflectors are provided inresonators which are one of components of the surface acoustic wavedevice. In the package of the frequency divider to which such surfaceacoustic wave devices are used, temperature of the devices becomes highduring operating so that large heat resistance is generated. As aresult, there is generated a case where initial operatingcharacteristics cannot be obtained so that stability of the operation islost. Here, it is considered that radiating fins are provided in thepackage of the frequency divider, but the package is increased in sizeso that the request in the market cannot be achieved. Such a problem isnot only true to the package of the frequency divider, but also togeneral surface acoustic wave apparatuses.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a technique capableof preventing protrusion of a soldering fillet applied on a side via.

Further, it is another object of the present invention to provide a thinsurface acoustic wave apparatus having predetermined electric frequencycharacteristics.

Further, it is another object of the present invention to provide asurface acoustic wave apparatus capable of efficiently conductingradiating of surface acoustic wave devices without increasing a packagein size.

In order to solve the above objects, an integrated circuit apparatusaccording to the present invention is configured by comprisingintegrated circuit devices in which predetermined circuit patterns areformed on a device substrate, and a package substrate comprising sidevias formed in a caved manner in the thickness direction on sidesurfaces on which the integrated circuit devices are mounted, wherein,when the side vias are each assumed to have the opening width φ and themaximum depth D, φ/2<D is assumed. According to such an invention, asoldering fillet applied on the side via is within the side via so thatit is possible to prevent protrusion of the soldering fillet applied onthe side via.

Further, in order to solve the above objects, a substrate unit accordingto the present invention is configured by comprising an integratedcircuit apparatus having integrated circuit devices in whichpredetermined circuit patterns are formed on a device substrate, and apackage substrate comprising side vias formed in a caved manner in thethickness direction on side surfaces on which the integrated circuitdevices are mounted, and a mounting substrate in which all electrodeselectrically connected to the integrated circuit apparatus are formed onthe inside of a device mounting area which is a mounting area of theintegrated circuit apparatus and the integrated circuit apparatus ismounted on the device mounting area. According to such an invention, theelectrode portions are arranged on the inside of the device mountingarea so that it is possible to prevent protrusion of the solderingfillet applied on the side via.

In order to solve the above objects, a surface acoustic wave apparatusaccording to the present invention is configured by comprising a devicemounting layer made of resin in which surface acoustic wave deviceshaving a predetermined bandpass center frequency are mounted on a devicemounting surface, a substrate connecting layer made of resin in whichexternal connecting terminals electrically connected to a mountingsubstrate are formed on a terminal forming surface facing in theopposite direction to the device mounting surface, at least one functionlayer made of resin which is provided between the device mounting layerand the substrate connecting layer and in which predetermined circuitpatterns and wirings are formed, and at least one throughhole which isformed from the device mounting layer through the function layer to thesubstrate connecting layer in a penetrating manner and electricallyconnects other portions than the portion between the device mountingsurface side and the terminal forming surface side to have open stubs.According to such an invention, since there is configured such thatpredetermined electric frequency characteristics can be obtained inconsideration of the open stubs, it is possible to prevent that thenumber of laminates is increased in order to avoid the open stubs andthe package is increased in size. Therefore it is possible to obtain athin surface acoustic wave apparatus having predetermined electricfrequency characteristics.

In order to solve the above objects, a surface acoustic wave apparatusaccording to the present invention is configured by comprising surfaceacoustic wave devices having a predetermined bandpass center frequencyand a package substrate in which the surface acoustic wave devices aremounted in a flip-chip mounting manner, wherein the surface acousticwave devices each comprise resonators for resonating with surfaceacoustic waves of a predetermined frequency, first electrodes whichelectrically connect the resonators and the package substrate and areconcerned with electric operation of the resonators, and secondelectrodes which are electrically connected to wirings other than theinput/output electrodes formed on the package substrate and are notconcerned with electric operation of the resonators. According to suchan invention, since heat generated during operating of the surfaceacoustic wave devices is propagated through the second electrodes to thewirings of the package substrate so that radiating is conducted, it ispossible to efficiently conduct radiating of the surface acoustic wavedevices without increasing the package in size.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a configuration of a frequency divideraccording to a first embodiment of the present invention;

FIG. 2 is a characteristic diagram showing the frequency divider in FIG.1;

FIG. 3 is a section view showing a package of the frequency divider inFIG. 1;

FIG. 4 is a schematic diagram showing a circuit of a surface acousticwave device which is a component of the frequency divider in FIG. 1;

FIG. 5 is a plan view showing a circuit layout on the periphery ofresonators in the surface acoustic wave device in FIG. 4;

FIG. 6 is a plan view showing part of a mounting substrate on which thefrequency divider in FIG. 1 is mounted;

FIG. 7 is an explanatory view showing a positional relationship betweenelectrode portions formed on the mounting substrate in FIG. 6 and sidevias of the frequency divider mounted on the mounting substrate;

FIG. 8 is an explanatory view showing a soldering fillet applied on theside via when the electrode portion of the mounting substrate is presenton the outside of a device mounting area;

FIG. 9 is an explanatory view showing a soldering fillet applied on theside via when the electrode portion of the mounting substrate is presenton the outermost side of the device mounting area;

FIG. 10 is an explanatory view showing a soldering fillet applied on theside via when the electrode portion of the mounting substrate is presenton the inside of the device mounting area;

FIG. 11 is an explanatory view showing side vias of a frequency divideraccording to a second embodiment of the present invention;

FIG. 12 is an explanatory view showing the side via in FIG. 11 in anenlarged manner;

FIG. 13 is an explanatory view showing side vias of a frequency divideraccording to a third embodiment of the present invention in an enlargedmanner;

FIG. 14 is a section view showing a package of a frequency divideraccording to a fourth embodiment of the present invention;

FIG. 15 is a section view showing a package of a frequency divideraccording to a fifth embodiment of the present invention;

FIG. 16 is a block diagram showing a configuration of a surface acousticwave device which is a component of a package of a frequency divideraccording to a sixth embodiment of the present invention; and

FIG. 17 is a section view showing a package of a conventional frequencydivider.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments according to the present invention will bedescribed in further detail with reference to the drawings. Here, in theaccompanying drawings, like numerals are denoted to like parts, andrepeated explanation is omitted. Additionally, the embodiments accordingto the invention are embodiments particularly useful for carrying outthe present invention, and the present invention is not limited to theembodiments.

FIG. 1 is a block diagram showing a configuration of a frequency divideraccording to a fist embodiment of the present invention, FIG. 2 is acharacteristic diagram of the frequency divider in FIG. 1, FIG. 3 is asection view showing a package of the frequency divider in FIG. 1, FIG.4 is a schematic diagram showing a circuit of a surface acoustic wavedevice which is a component of the frequency divider in FIG. 1, FIG. 5is a plan view showing a circuit layout on the periphery of resonatorsin the surface acoustic wave device in FIG. 4, FIG. 6 is a plan viewshowing part of a mounting substrate on which the frequency divider inFIG. 1 is mounted, FIG. 7 is an explanatory view showing a positionalrelationship between electrode portions formed on the mounting substratein FIG. 6 and side vias of the frequency divider mounted on the mountingsubstrate, FIG. 8 is an explanatory view showing a soldering filletapplied on the side via when the electrode portion of the mountingsubstrate is present on the outside of a device mounting area, FIG. 9 isan explanatory view showing a soldering fillet applied on the side viawhen the electrode portion of the mounting substrate is present on theoutermost side of the device mounting area, FIG. 10 is an explanatoryview showing a soldering fillet applied on the side via when theelectrode portion of the mounting substrate is present on the inside ofthe device mounting area, FIG. 11 is an explanatory view showing sidevias of a frequency divider according to a second embodiment of thepresent invention, FIG. 12 is an explanatory view showing the side viain FIG. 11 in an enlarged manner, and FIG. 13 is an explanatory viewshowing a side via of a frequency divider according to a thirdembodiment of the present invention in an enlarged manner. In FIGS. 7and 11, only the side vias of the frequency divider are illustrated, andother wirings, electrodes, and the like are omitted.

In the frequency divider which is the surface acoustic wave apparatus(integrated circuit apparatus) shown in FIG. 1, two surface acousticwave devices (integrated circuit devices) F₁ and F₂ have mutuallydifferent bandpass center frequencies f₁ and f₂, respectively, as shownin FIG. 2. In order to configure the frequency divider with such surfaceacoustic wave devices F₁ and F₂, phase adjusting circuits P₁ and P₂ foreliminating interference of filter characteristics of the respectivesurface acoustic wave devices F₁ and F₂ are provided.

The phase adjusting circuits P₁ and P₂ are connected to common terminalsT₁ and T₂, respectively, and further the surface acoustic wave devicesF₁ and F₂ are connected to the phase adjusting circuits P₁ and P₂,respectively. Further, input/output terminals S₁ and S₂ offrequency-divided signals are connected to the surface acoustic wavedevices F₁ and F₂, respectively.

In such a frequency divider 10, as shown in FIG. 3, a device mountinglayer 1 a on which the two surface acoustic wave devices F₁ and F₂described above are mounted is positioned at the uppermost layer, aground layer 11 b in which ground electrodes are formed, a circuitforming layer 11 c in which high frequency circuits such as the phaseadjusting circuits P₁ and P₂ are formed, and a substrate connectinglayer 11 d in which external connecting electrodes 12 are formed arepositioned toward the lower layers from the device mounting layer 11 a,and they are connected with each other to form a package substrate 11which forms a laminate structure. Such a package substrate 11 is made ofceramics or resin.

The surface acoustic wave devices F₁ and F₂ are each configured in whicha predetermined conductive pattern is formed on a piezoelectricsubstrate (device substrate). The piezoelectric substrate is made ofpiezoelectric monocrystal such as LiNbO₃, LiTaO₃, or crystalline quartz,or piezoelectric ceramics such as lead zirconate titanate basedpiezoelectric ceramics. But there may be employed a piezoelectricsubstrate in which a piezoelectric thin film such as ZnO thin film isformed on an insulating substrate. The surface acoustic wave devices F₁and F₂ are airtightly sealed by a cap 13 so that it is protected fromdust, mechanical impact, and the like.

In a mounting substrate 23 on which such a frequency divider 10 ismounted, a plurality of electrode portions 24 corresponding to theexternal connecting electrodes 12 are formed. The external connectingelectrodes 12 and the electrode portions 24 are electrically andmechanically connected so that the frequency divider 10 is fixed on themounting substrate 23 to configure a substrate unit. In the presentembodiment, the package substrate 11 has four layers, but may have onelayer or a plurality of layers other than four layers. Further, whenillustrated, the surface acoustic wave devices F₁ and F₂ areelectrically connected to the package substrate 11 through projectingelectrodes 14, but may be connected through wires.

Here, respective interlayers of the package substrate 11 areappropriately connected in an electric manner via throughholes 15 formedin a penetrating manner, side vias 16 formed in a caved manner in thethickness direction on the side surfaces, and the like, and wirings 17such as microstrip lines are formed on the layer surface. As shown inFIG. 4, resonators 18 resonating with surface acoustic waves of apredetermined frequency are formed on the piezoelectric substrate of thesurface acoustic wave device F₁, F₂. An input electrode 19 whichelectrically connects the resonators 18 and the package 11 and to/fromwhich electric signals for the resonators 18 are input/output, an outputelectrode 20, and a ground electrode 21 are electrically connected tothe resonators 18 via the wirings 17.

As shown in FIG. 5, the resonator 18 is configured in teeth shape of apair of combs which is meshing each other. When voltage is applied tothe resonator 18 at the input side to generate an electric field, asurface acoustic wave is generated on the piezoelectric substrate by apiezoelectric effect. Further, a mechanical distortion due to the thusgenerated surface acoustic wave generates an electric field, which isconverted to an electric signal in the resonator 18 at the output side.Reflectors 22 for reflecting surface acoustic waves are arranged on bothsides of the resonator 18.

Additionally, when illustrated, the wirings 17 between the inputelectrode 19 and the output electrode 20 are serial arm, and parallelarms which are a plurality of wirings 17 between the serial arm and theground electrodes 21 are configured so that a ladder type circuit inwhich the resonators 18 are arranged in the serial arm and parallel armmanner, but the surface acoustic wave devices F₁ and F₂ may employ otherthan such a circuit configuration.

As shown in FIG. 6, electrode portions 24 formed on the mountingsubstrate 23 on which the frequency divider 10 is mounted are allarranged on the inside of a device mounting area A which is a mountingarea of the frequency divider 10. The inside of the device mounting areain this specification means the concept including border portionsbetween the device mounting area A and other areas. Therefore, theelectrode portions 24 may be formed in contact with the border portions,and formed inside without being contacted with the border portions. Aslong as the electrode portions 24 are arranged on the inside of thedevice mounting area A, the layout pattern thereof can be freely set.

Since the electrode portions 24 are formed on the inside of the devicemounting area A, the electrode portion 24 corresponding to the frequencydivider 10 is not present on the outside of the package substrate 11 ofthe frequency divider 10 mounted on the device mounting area A of themounting substrate 23 as shown in FIG. 7.

Here, when the electrode portion 24 is present on the outside of thedevice mounting area A, a soldering fillet applied on a side via isshown in FIG. 8. Since the soldering fillet 25 is spread from the lowerportion of the side via 16 to the whole exposed surface of the electrodeportion 24 or it is expanded out of the electrode portion 24 in aprotruded manner when the applied amount is large, the soldering fillet25 is protruded outward when illustrated in FIG. 8. As a result, themounting area of the frequency divider 10 becomes larger due to such asoldering fillet 25 so that the high density mounting cannot beconducted.

On the contrary, when the electrode portions 24 are arranged on theinside of the device mounting area A as in the present embodiment, thecases shown in FIGS. 9 and 10 are taken. In other words, when theelectrode portion 24 of the mounting substrate 23 is present on theoutermost side of the device mounting area A (FIG. 9), and the electrodeportion 24 of the mounting substrate 23 is present on the inside of thedevice mounting area A (FIG. 10), the soldering fillet 25 applied on theside via 16 is similarly spread over the whole exposed surface of theelectrode portion 24, but the electrode portion 24 itself is arranged onthe inside of the device mounting area A so that the soldering fillet 25is not also protruded from the device mounting area A. As describedabove, since the protrusion of the soldering fillet 25 applied on theside via 16 is prevented, the mounting area of the frequency divider 10can be made small to the outer size of the package substrate 11, therebyperforming the high density mounting.

Here, as shown in FIGS. 12 and 13, when the side via 16 formed on thepackage substrate 11 of the frequency divider 10 is assumed to have theopening width φ and the maximum depth D, φ/2<D is assumed. Further, theshape along the substrate surface of the package substrate 11 in theside via 16 may have a shape forming part of an oval as shown in FIG.12, or a shape forming part of an ellipse as shown in FIG. 13.Additionally, as long as the condition of φ/2<D is satisfied, the shapeis not particularly limited, and may be, for example, triangle,quadrangle, or the like.

As described above, since the side via 16 is made to the size of φ/2<Dso that the soldering fillet 25 applied on the side via 16 is within theside via 16 and the protrusion thereof can be prevented, the mountingarea of the frequency divider 10 can be made small to the outer size ofthe package substrate 11 so that the high density mounting can beperformed. Additionally, the technique for arranging the electrodeportions 24 of the mounting substrate 23 on the inside of the devicemounting area A and the technique for making the side vias 16 to thesize of φ/2<D can be independently used, and both used.

In the above description, the example in which the present invention isapplied to the frequency divider 10 is shown, but the present inventionis not limited to the frequency divider 10, and can be applied tovarious surface acoustic wave apparatuses on which one or a plurality ofsurface acoustic wave devices are mounted. Further, the presentinvention is not limited to such surface acoustic wave apparatuses, canbe applied to various integrated circuit apparatuses in which integratecircuit devices where predetermined circuit patterns are formed on adevice substrate such as a piezoelectric substrate or a siliconsubstrate is mounted on a package substrate.

As can be seen from the above description, it is possible to obtain thefollowing effects according to the present invention. Since theelectrode portions are arranged on the inside of the device mountingarea, it is possible to prevent the protrusion of the soldering filletapplied on the side via. Further, since the soldering fillet applied onthe side via is within the side via, it is possible to prevent theprotrusion of the soldering fillet applied on the side via. As describedabove, since it is possible to prevent the protrusion of the solderingfillet applied on the side via, the mounting area of the integratedcircuit apparatus can be made small to the outer size of the packagesubstrate so that the high density mounting can be performed.

FIG. 14 is a section view showing a frequency divider according to afourth embodiment of the present invention. In the package 110 of thefrequency divider, a device mounting layer 111 in which the two surfaceacoustic wave devices F₁ and F₂ described above are mounted on a devicemounting surface 111 a is positioned at the uppermost layer, a groundlayer (function layer) 112 in which ground electrodes are formed, acircuit forming layer (function layer) 113 in which high frequencycircuits such as the phase adjusting circuits P₁ and P₂ are formed, andthe lowermost layer which is a substrate connecting layer 114 in whichcommon ground electrodes or external connecting terminals 115 are formedare positioned toward the lower layers from the device mounting layer111, and they are connected with each other to form a laminatestructure.

These layers 111 to 114 are all made of resin. As illustrated, in thesubstrate connecting layer 114, a terminal forming surface 114 a inwhich the external connecting terminals 115 electrically connected tothe mounting substrate are formed faces in the opposite direction to thedevice mounting surface 111 a of the device mounting layer 111. Thesurface acoustic wave devices F₁ and F₂ are airtightly sealed by a cap116 to be entirely packaged.

In the present embodiment, the function layer is configured with the twolayers of the ground layer 112 and the circuit forming layer 113, butmay be configured with one layer or three or more layers, and wirings orthe predetermined circuit patterns can be formed in the layer ifnecessary. Further, when illustrated, the surface acoustic wave devicesF₁ and F₂ are electrically connected to the device mounting layer thoughbumps 117, but may be connected through wires.

Here, since the layers 111 to 114 are made of resin, the respectiveinterlayers are appropriately connected via throughholes 118 in anelectric manner. The throughholes 118 are formed from the devicemounting layer 111 through the ground layer 112 and the circuit forminglayer 113 to the substrate connecting layer 114 in a penetrating manner,and have conductive members injected therein. In such throughholes 118,some electrically connect between the device mounting surface 111 a sideand the terminal forming surface 114 a side, and others electricallyconnect other portions than the above portion (when illustrated, betweenthe ground layer 112 and the circuit forming layer 113, between thedevice mounting layer 111 and the ground layer 112, and between theground layer 112 and the opposite surface of the terminal formingsurface 114 a of the substrate connecting layer 114).

Here, the latter throughholes 118 penetrate the substrate connectinglayer 114 which is the lowermost layer or the device mounting layer 111which is the uppermost layer, but wirings are not extended therefrom andopen stubs 119 are formed. In the frequency divider, in consideration ofvariation of the frequency characteristics by the open stubs 119, thatis such open stubs 119, line width, line length, and the like are set soas to obtain predetermined electric frequency characteristics.

The package (surface acoustic wave apparatus) 110 of the frequencydivider according to the present embodiment is manufactured in thefollowing manner. At first, copper foil is applied on the substratematerials made of resin forming the respective layers 111 to 114, andetching is performed to form predetermined circuit patterns or wiringpatterns. Then these are aligned with each other to be adhered, and apackage with a laminate structure is formed.

Next, the throughholes 118 are formed and injected with a conductivemember such as copper, and the surface acoustic wave devices F₁ and F₂are mounted on the device mounting layer 111 by ultrasonic wave. Thethroughholes 118 may be injected with an insulating member. Finally, thesurface acoustic wave devices F₁ and F₂ are airtightly sealed using thecap 116.

According to the package 110 of the frequency divider described above,since the predetermined electric frequency characteristics can beobtained in consideration of the open stubs 119, it is possible toprevent that the number of laminates is increased in order to avoid theopen stubs 119 and the package becomes larger in size. Therefore, it ispossible to obtain the package 110 of the thin frequency divider havingthe predetermined electric frequency characteristics. Further, since thepresence of the open stubs 119 can be allowed, it is possible toconfigure the package 110 of the frequency divider whose layer materialemploys resin which cannot form via holes connecting only the requiredinterlayers, thereby achieving cost reduction.

In the above description, the example in which the present invention isapplied to the package 110 of the frequency divider is shown, but thepresent invention is not limited to the package 110 of the frequencydivider, and can be applied to surface acoustic wave apparatuses such asvarious surface acoustic wave filtering apparatuses on which surfaceacoustic wave filtering devices, that is one or a plurality of surfaceacoustic wave devices are mounted. Therefore, the scope of applicationof the present invention is not limited to a filter, and can be appliedto various fields other than filter.

As can be seen from the above description, it is possible to obtain thefollowing effects according to the present invention. Since there isconfigured such that the predetermined electric frequencycharacteristics can be obtained in consideration of the open stubs, itis possible to prevent that the number of laminates is increased inorder to avoid the open stubs and the package becomes larger in size.Therefore, it is possible to obtain a thin surface acoustic waveapparatus having the predetermined electric frequency characteristics.Since the presence of the open stubs can be allowed, it is possible toconfigure the surface acoustic wave apparatus whose layer materialemploys resin which cannot form via holes connecting only the requiredinterlayers, thereby achieving cost reduction.

FIG. 15 is a section view showing a frequency divider according to afifth embodiment of the present invention. In a package (surfaceacoustic wave apparatus) 210 of this frequency divider, a devicemounting layer 211 a on which the two surface acoustic wave devices F₁and F₂ described above are mounted is positioned at the uppermost layer,a ground layer 211 b in which ground electrodes are formed, a circuitforming layer 211 c in which high frequency circuits such as the phaseadjusting circuits P₁ and P₂ are formed, and a substrate connectinglayer 211 d in which common ground electrodes or external connectingterminals 212 are formed are positioned toward the lower layers from thedevice mounting layer 211 a, and they are connected with each other toform a package substrate 211 forming a laminate structure.

The package substrate 211 is made of ceramics or resin. The surfaceacoustic wave devices F₁ and F₂ are airtightly sealed by a cap 213 to beentirely packaged. In the present embodiment, the package substrate 211has four layers, but may have one layer or a plurality of layers otherthan four layers. Here, the respective interlayers of the packagesubstrate 211 are appropriately connected by throughholes, via holes, orwirings 215 such as sidewall wirings formed on the side surfaces in anelectric manner, and the wirings 215 such as microstrip lines are formedon the layer surface.

As shown in FIG. 16, the surface acoustic wave devices F₁ and F₂ whichare components of the package 210 of the frequency divider each compriseresonators 217 resonating with surface acoustic waves of a predeterminedfrequency. An input electrode (first electrode) 218 which electricallyconnects the resonators 217 and the package substrate 211 and isconcerned with the electric operation of the resonator 217, an outputelectrode (first electrode) 219, and a ground electrode (firstelectrode) 220 are connected to the resonators 217 via wirings 221.

Further, radiating electrodes (second electrodes) 222 which areelectrically connected to the wirings other than the input/outputelectrodes formed in the package substrate 211 and which are notconcerned with the electric operation of the resonators 217, that isdummy electrodes are formed. Here, the wirings other than theinput/output electrodes specifically means wirings connected with theground electrodes of the package substrate 211, or wirings which aremerely laid and whose potentials are inconstant. Additionally, theelectrodes 218, 219, 220, 222, and the package substrate 211 arebump-connected by ultrasonic wave where the electrodes 218, 219, 220,222 are set to be projecting electrodes 214.

Here, the resonators 217 are each configured with an electrode 217 a ina crossing-fingers shape (teeth shape of a comb) for converting thesurface acoustic waves to electric signals, and a reflector 217 b forreflecting the surface acoustic waves. Some radiating electrodes 222 aredirectly, or electrically connected via the wirings 221 to thereflectors 217 b. Further, other radiating electrodes 222 are providedindependent of the resonators 217 and the electrodes 218, 219, and 220.

As described above, since the radiating electrodes 222 are not concernedwith the electric operation of the resonators 217, even when theradiating electrodes 222 and the resonators 217 are electricallyconnected, an electric signal is not flowed to the radiating electrodes222. Further, the radiating electrodes 222 may be in the form of beingelectrically connected to the reflectors 217 b, or in the form of beingprovided independent of the resonators 217 and the electrodes 218, 219,and 220.

The package 210 of the frequency divider according to the presentembodiment is manufactured in the following manner. As first,predetermined circuit patterns or wiring patterns are formed on thesubstrate materials structuring the respective layers 211 a to 211 d byusing the thin film forming technique. Then these are aligned with eachother to be adhered, and a package with a laminate structure isconfigured. Next, the surface acoustic wave devices F₁ and F₂ aremounted on the device mounting layer 211 a by ultrasonic wave, and thesurface acoustic wave devices F₁ and F₂ are airtightly sealed using thecap 213.

According to the aforementioned package 210 of the frequency divider, asdescribed above, the radiating electrodes 222 which are electricallyconnected with the wirings other than the input/output electrodes formedon the package substrate 211 and which are not concerned with theelectric operation of the resonators 217 are formed in the surfaceacoustic wave devices F₁ and F₂. Therefore, heat generated during deviceoperating is propagated though the radiating electrodes 222 to thewirings of the package substrate 211 so that radiating is conducted.Thereby, it is possible to efficiently conduct radiating of the surfaceacoustic wave devices F₁ and F₂ without increasing the package in size.Particularly, when the radiating electrodes 222 are electricallyconnected with the reflectors 217 b, it is possible to efficientlyconduct radiating of the reflectors 217 b whose temperature becomeshigher during operating of the surface acoustic wave devices F₁ and F₂.

In the above description, the example in which the present invention isapplied to the package 210 of the frequency divider is shown, but thepresent invention is not limited to the package 210 of the frequencydivider, and can be applied to surface acoustic wave apparatuses such asvarious surface acoustic wave filtering apparatuses on which surfaceacoustic wave filtering devices, that is one or a plurality of surfaceacoustic wave devices are mounted. Therefore, the scope of applicationof the present invention is not limited to a filter, and can be appliedto various fields other than filter.

As can be seen from the above description, it is possible to obtain thefollowing effects according to the present invention. Since secondelectrodes which are electrically connected to the wirings formed on thepackage substrate into which input/output signals are not flowed andwhich are not concerned with the electric operation of the resonatorsare formed on the surface acoustic wave devices, heat generated duringdevice operating is propagated through the second electrodes to thewirings of the package substrate so that it is possible to efficientlyconduct radiating of the surface acoustic wave devices withoutincreasing the package in size. Particularly, when the radiatingelectrodes and the reflectors are electrically connected, it is possibleto efficiently conduct radiating of the reflectors whose temperaturebecomes maximum during operating of the surface acoustic wave devices.

1. A package substrate comprising: a device mounting layer made of resinin which a conductive portion is formed on a device mounting surface;circuit devices mounted on said device mounting surface and electricallyconnected to said conductive portion; a substrate connecting layer madeof resin in which external connecting terminals connected to a mountingsubstrate are formed; at least one function layer made of resin which isprovided between the device mounting layer and the substrate connectinglayer and in which predetermined circuit patterns and wirings areformed; and at least one throughhole which is formed from the devicemounting layer through the function layer to the substrate connectinglayer in a penetrating manner with open stubs and which electricallyconnects said predetermined circuit patterns to each other; and firstelectrical connection between the conductive portion on said devicemounting surface and the predetermined circuit patterns, secondelectrical connection between the conductive portion on said devicemounting surface and the external connecting terminals, third electricalconnection between the predetermined circuit patterns and the externalconnecting terminals, and fourth electrical connection between thepredetermined circuit patterns being achieved only by the use of saidthroughhole formed from the device mounting layer through the functionlayer to the substrate connecting layer in the penetrating manner.
 2. Asurface acoustic wave apparatus comprising: a device mounting layer madeof resin in which a conductive portion is formed on a device mountingsurface; surface acoustic wave devices mounted on said device mountingsurface and having a predetermined bandpass center frequency, saidsurface acoustic wave devices being electrically connected to saidconductive portion; a substrate connecting layer made of resin in whichexternal connecting terminals electrically connected to a mountingsubstrate are formed on a terminal forming surface facing in theopposite direction to the device mounting surface; at least one functionlayer made of resin which is provided between the device mounting layerand the substrate connecting layer and in which predetermined circuitpatterns and wirings are formed, said predetermined circuit patternsbeing positioned mutually in the stacked direction; and at least onethroughhole which is formed from the device mounting layer through thefunction layer to the substrate connecting layer in a penetrating mannerwith open stubs and which electrically connects said predeterminedcircuit patterns to each other; and first electrical connection betweenthe conductive portion on said device mounting surface and thepredetermined circuit patterns, second electrical connection between theconductive portion on said device mounting surface and the externalconnecting terminals, third electrical connection between thepredetermined circuit patterns and the external connecting terminals,and fourth electrical connection between the predetermined circuitpatterns being achieved only by the use of said throughhole formed fromthe device mounting layer through the function layer to the substrateconnecting layer in the penetrating manner.
 3. A surface acoustic waveapparatus according to claim 2, wherein a conductive member orinsulating member is injected into the throughhole.
 4. A surfaceacoustic wave apparatus according to claim 3, wherein two surfaceacoustic wave devices having mutually different bandpass centerfrequencies are mounted on the device mounting surface.
 5. A surfaceacoustic wave apparatus according to claim 2, wherein two surfaceacoustic wave devices having mutually different bandpass centerfrequencies are mounted on the device mounting surface.
 6. A surfaceacoustic wave apparatus according to claim 2, wherein surface acousticwave devices are electrically connected to the device mounting layer viabumps.
 7. A surface acoustic wave apparatus according to claim 2,wherein the function layer includes phase adjusting circuits.